With the development of the modern society, there are growing interests in the importance of personal identification and personal information security. The fingerprint recognition technology is characterized by high safety, high reliability and simple operation because of uniqueness and invariability of a human fingerprint. Thus the fingerprint recognition technology is widely used in various fields for protecting personal information security. Meanwhile, with the development of science and technology, the information security issue of various electronic products has long been a concern in technology development. The need for information security is even more acute in mobile terminals, such as a cell phone, a laptop computer, a tablet computer, and a digital camera.
A fingerprint recognition device senses a fingerprint in a capacitive (electric-field) manner or an inductive manner. The fingerprint recognition device extracts a user fingerprint, converts the user fingerprint into an electrical signal and outputs the electrical signal, thereby acquiring fingerprint information of the user. Specifically, as shown in FIG. 1, which is a schematic cross-sectional structural diagram of a fingerprint recognition device, which includes a base plate 100, a fingerprint recognition chip 101 coupled to a surface of the base plate 100, and a glass base plate 102 covering a surface of the fingerprint recognition chip 101.
Taking a capacitive fingerprint recognition chip as an example, the fingerprint recognition chip 101 includes one or more capacitor plates. Since the epidermis or subdermal layer of a user's finger has raised ridges and recessed valleys, a distance between the ridge and the fingerprint recognition chip 101 is different from a distance between the valley and the fingerprint recognition chip 101 when the user's finger 103 touches a surface of the glass base plate 102. Therefore, a capacitance value between the ridge of the user's finger 103 and the capacitor plate is different from a capacitance value between the valley of the user's finger 103 and the capacitor plate. The fingerprint recognition chip 101 is capable of acquiring the different capacitance values, converting them into corresponding electrical signals and outputting the electrical signals. After gathering the received electrical signals, the fingerprint recognition device can acquire the fingerprint information of the user.
However, the conventional fingerprint recognition device has a high requirement on the sensitivity of the fingerprint recognition chip, limiting the fabrication and application of the fingerprint recognition device.